So there are few things which make me doubt Alea Evangelii as a Tafl game:

CCC MS 122 was written in the 12th century by an Irish monk referencing a manuscript from over a century earlier written by Dub Innse, Bishop of Bangor, who brought the game back to Ireland from the court of Aethelstan, King of England(927-939). It was conveyed to him by a Frank and a 'Wise Roman', who was Israel(The Grammarian). Israel's manuscripts are written in latin with glosses written in Breton which tends to indicate he himself was likely a Breton that had fled the persecution of Bretons common in Frankia at that time. That a Frank and a Breton would create or teach a Tafl game seems unlikely, though not impossible, considering how recent the Duchy of Normandy(911) was formed which would have marked the beginings of peaceful cultural exchanges between the Franks and Norse.

Isidore of Seville, who is likely to have been known to the author of CCC MS 122, Dub innse, and Israel the Grammarian, in his manuscript Etymologiae(c. 600–625), an etymological encyclopedia, wrote about Alea:

On Tabula. Alea, that is, the board game, was invented by the Greeks during the lulls in the Trojan War by a certain soldier named Alea, from whom the practice takes its name. The board game is played with a dice tumber, stones, and dice.

R.C. Bell in his book Board and Table Games from Many Civilizations postulates that towards the end of the 6th century the name Tabula was replaced by Alea citing this passage. H.J.R Murray, however, in A History of Board-Games Other Than Chess states the changes in terminology was from Alea to Tabula. Regardless the link between Alea and dice in games and games of chance defines the use of Alea in Latin.

In A Dictionary of Greek and Roman Antiquities by John Murray Alea is defined as:

ALEA, gaming, or playing at a game of chance of any kind. Hence, alea, aleator, a gamester, a gambler. Playing with tali or tesserae was generally understood; because these were by far the most common games of chance among the Romans.

Alea sometimes denotes the implement used in playing, as in the phrase jacta alea est, "the die is cast," uttered by Julius Caesar, immediately before he crossed the Rubicon

Furthermore Latin Learning and English Lore: Studies in Anglo-Saxon Literature by Katherine O'Brien O'Keeffe and Andy Orchard cites a Latin-Irish glossary from c. 1100 which defines Alea as the Gaelic Taiplis which referenced Tabula/Tables/Backgammon prior to the arrival of Draughts for which its modern meaning implies.

So it would seem the word Alea is inextricably linked to games of chance and Israel being one of the foremost European scholars of the era would not have misused the term when naming the game. Also I find it unlikely that Dub Innse or the unnamed author of CCC MS 122 would be unfamiliar with the use of the term considering both were clergymen and Isidore's works were very prominent as well as both being Irish and that contemporary Latin-Irish glossary linking Alea to the Gaelic word for Tabula. That is why I find it hard to overlook a name which effectively boils down to Gospel Dice or Gospel Gambling and that the somewhat radial symmetry of the diagram is overshadowed by it.

Interesting stuff! I need to reread the language analysis more carefully, but here are my initial thoughts on a quick read through. I think there are some fair points here, the evidence for Alea is full of holes, and it is only one source, seen in the context of a few other patchy tafl sources. Its great to have someone looking hard at the language at last.

People thinking tafl games were played with dice due to confusing them with the name 'tables' for backgammon has been through the mill many times. Interestingly its the word Alea causing the same suspicion here! The tables confusion no doubt comes from cross translations as the vikings moved about. Tavle in Norwegian means blackboard in english. Tafl (means table) Brett (means board as in game board) bord (means table). enough to confuse anyone. Then some wiseguy calls backgammon 'tables'. Genius. And the welsh opted for Tawlbwrdd, thanks Wales.

I think the argument that its a visual coincidence is stretching things a bit. One thing Alea certainly does not look like is any form of backgammon or race game. The similarity to Tafl games though is striking. A cross form, four fold symmetry, the number of pieces dividing easily into the right number of black and white for this sized board, plus a king. That's some coincidence. Plus the odd number board grid.

I've never been one to support the idea of dice in tafl games, mainly because I don't like chance coming into a strategy game. But I wouldn't rule it out and would enjoy trying it if any evidence for such rules comes to light.

Finally, there is something to the idea that this was never even a game, just some fanciful scriblings, on the grounds that its just too unwieldy to be any fun. I would put forward two counter arguments to consider. Monopoly, and roleplaying games are very popular, and can go on for days. A good game of Risk can be the same. All dice games though, maybe Alea with dice IS a good idea!

My other argument is that a look at the medieval ALFONSO X’ 'Book of Games' suggests a popularity of chess and other variants on larger boards with more pieces. Astrological Checkers, and 'Great Chess' are notable examples and impressively large.

So, does Alea belong in the Tafl family? It looks like it does, but is that enough? Alea, and all tafl games are conspicuously absent from the Book of Games, where even Tic tac toe gets a page to itself. But we know Tablut was around until the 1700s. And we know A tafl game was around in Wales around the same time as Alea. And we know the Irish had a tafl game. So I would conclude its not a big leap of the imagination to say its a Tafl game.

With that said, I will look at the translation arguments in more depth and post again!